Last Thursday evening at Montclair State University in New Jersey, after a two-hour talk on activism and education, terrorist emeritus Bill Ayers took one final question.

“Thank you, Sir, thank you, thank you,” said the questioner, while a friend videotaped the exchange. “Time magazine columnist Joe Klein wrote that President Obama’s book, “Dreams from My Father,” quote, ‘may be the best written memoir ever produced by an American politician.'”

“I agree with that,” Ayers chipped in before the question could be asked.

“What is your opinion of Barack Obama’s style as a writer and uh …”

“I think the book is very good. The second book [“Audacity of Hope”] is more of a political hack book, but uh, the first book is quite good.”

Then when the questioner moved on to another topic – “Also, you just mentioned the Pentagon and Tomahawk” – Ayers pulled the conversation back to “Dreams from My Father.”

“Did you know that I wrote it, incidentally?” he said with a straight face, the first time he had made this admission with a presumably hostile video camera pointed at him.

A colleague, who contributed to my literary detective work on “Dreams” and has seen the video in question, makes a knowing observation on the exchange to this point.

“The at-first deadpan delivery is [Ayers’] emotional catharsis, his relief valve and his prisoner’s shank between Obama’s ribs,” he writes. “But it’s delivered with resignation, knowing [Ayers] can never do anything but lightly sneer while Bambi walks off with the reputation and the big bucks.”

When the questioner’s friends in the audience affirmed Ayers’ authorship, “Yeah, we know that,” Ayers retreated once again into irony.

“You wrote that?” asked the questioner, “Yeah, yeah,” said Ayers, “and if you help me prove it, I’ll split the royalties with you. Thank you very much.”

“He is brilliant, deft,” my colleague says of Ayers. “I think he has found a near perfect, near impregnable defense: Tell the truth and sneer. How can this ever possibly be defeated?”

With his final comment, Ayers prodded the friendly audience to laughter. They laughed in relief. Until this moment, they feared where the conversation was heading.

This is the power that Ayers now exercises: He holds the reputation of the president in his hands. If the audience laughed nervously upon hearing his final ironic jab, and if the media will laugh nervously upon seeing the video, the White House is not laughing at all.

As Barack Obama knows, as Bill Ayers knows, as I know, and now as the people who have read my book, “Deconstructing Obama,” know, Bill Ayers is the principal craftsman of “Dreams.” The evidence, when accumulated in one source, overwhelms all but the willfully blind.

If, however, Ayers were to confirm his role, he would lose his leverage over the president and, I suspect, a lot of friends. But as the president continues on a military course toxic to the hard left, Ayers’ one recourse is to remind the president of the cards he still holds.

In the exchange at Montclair State, Ayers did this by adding new information to the debate. He made an unprompted and legitimate distinction between his “Dreams” and an “Audacity” he knows to have been produced by committee. In doing so, he undermined Obama’s claim to the unique authorship of both.

Ayers knows something else, namely that he and Obama contrived much of the story they told in “Dreams.” Donald Trump’s willingness to probe on this point only enhances Ayers’ leverage.

The success of “Dreams” has had to eat at Ayers. I suspect that when his memoir, “Fugitive Days,” was published 10 years ago, he had high expectations. He led a much more eventful life than Obama and, given his control over the subject matter, his story is more tightly told.

When the New York Times weighed in with a sober, lengthy and exquisitely nonjudgmental review of his book, titled “No regrets for a love of explosives,” Ayers had to believe he had a best-seller on his hands.

That belief died quickly. Within hours of the paper’s release, on that memorable Sept. 11 day, more lethal terrorists than Ayers had suddenly thrown his “love” into disrepute. If not literally, certainly emotionally, Ayers was forced underground again.

The spectacular mistiming of “Fugitive Days” doomed the book to short-term infamy and long-term obscurity. With Obama’s emergence in 2004, Ayers found himself playing the deformed Cyrano to Obama’s hunky Christian, and it was Christian who was winning the heart of Roxanne/America.

Worse for Ayers, once I went public with my belief that he had largely written “Dreams,” my critics found it necessary to attack his skills as a writer to reaffirm Obama’s.

I cite the following quote from Republican leader Ken Blackwell only because it captures the blowback I routinely faced from both sides of the aisle.

“Obama’s book is a classic of American literature,” Blackwell wrote in 2009. “Those who think he did not write it, that perhaps, as some Internet zanies have alleged, that the radical Bill Ayers wrote it, are doing both Obama and themselves a disservice. Bill Ayers’ thoughts have all the leaden quality of most deadening Marxist screeds. Ayers’ writing you can’t pick up; Obama’s you can’t put down.”

Ayers and I now have an unlikely bond: Only I can rescue his literary reputation. And I can do so only if he rescues mine. Their media are no more likely to believe an “Internet zany” than ours are to believe an “unrepentant terrorist.”